<!DOCTYPE html>
<html lang="zh-CN">

<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>zRender</title>
</head>

<body class="app">
    <div class="title">
        
    </div>
     <div id="main" style="width:500px;height:500px;border:1px solid skyblue;">

     </div>
     <button class="btn">click me</button>
    
</body>

</html>